Under a Phase I SBIR grant from the National Institutes Of Health, Mechanical Technology Incorporated (MTl) has successfully demonstrated the technology of an innovative magnetic Screw (magscrew) actuator for possible use in a total artificial heart (TAH) developed by the Cleveland Clinic Foundation (CCf). Accordingly, this Phase II application describes a joint MTI/CCF program to advance the magscrew actuator design to the level of a fully Integrated TAH subsystem. Additionally, four TAH systems will be built to support both in vitro and in vivo testing. Despite great progress in the prevention and treatment of heart disease, cardiac failure remains the leading cause of death in the United States. Many additional patients are Incapacitated by low cardiac output. In 1991, the Institute of Medicine published a report strongly endorsing continued work on artificial heart research. lt is this social need and commercial opportunity that the MTI/CCF team will address with a next-generation actuator adaptable to both heart assist and heart replacement devices. The ultimate goal of this research is to obtain FDA approval to use the CCF/MTI TAH for investigational clinical trials, and to subsequently gain full regulatory approval to make it available as a clinical product. PROPOSED COMMERCIAL APPLICATIONS The magscrew actuator will be an enabling subsystem (in terms of commercially acceptable life and reliability) for both ventricular assist devices (VADs) and the permanent implantable TAH. According to a 1991 report published by the Institute Of Medicine, there could be 35,000 to 70,000 primary candidates annually for mechanical Circulatory support systems (MCSSs) by year 2010. While most would require VADs, as many as 10,000 to 20,000 cases may justify the use of a TAH. By year 2020, there may be as many as 200,000 secondary candidates for MCSSs. These estimates assume that at least one approved VAD is available by 1999, and that at least one approved TAH 15 available in the early 2000s